With rumors swirling of performance DDR3 memory not playing nice with Core i7 platforms due to voltage requirements, it's not a bad idea to wait for specifically compatible kits to emerge before upgrading your RAM. In addition to getting the voltage right, upcoming triple-channel kits will ship with three sticks of RAM to take advantage of the new architecture.
First out of the gate with a line of triple-channel kits is Corsair, who today announced no less than six high performance kits designed for Core i7. These include:
6GB kit 1866MHz Dominator with Airflow fan (TR3X6G1866C9DF - $475
3GB kit 1866MHz Dominator with Airflow fan (TR3X3G1866C9DF) - $250
Latency timings and voltage information is still trickling out for many of the kits. Corsair's press release indicates the kits are available now, though we've been unable to spot them in the wild. We imagine the usual culprits (Newegg, ZipZoomFly, TigerDirect, etc.) will show stock very soon.